def _apple_of_day_one(apple: int, day: int):
    if day == 1:
        return apple
    return _apple_of_day_one((apple + 1) * 2, day - 1)


def _main():
    print(f"第一天摘了 {_apple_of_day_one(1, 7)} 个苹果。")


if __name__ == "__main__":
    _main()
